The molecule 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) is an organic semiconductor with outstanding performance in thin-film transistors. The asymmetric shape of the molecule causes an unusual phase behavior, which is a result of a distinct difference in the molecular arrangement between the head-to-head stacking of the molecules versus head-to-tail stacking. Thin films are prepared at elevated temperatures by crystallization from melt under controlled cooling rates, thermal-gradient crystallization, and bar coating at elevated temperatures. The films are investigated using X-ray diffraction techniques. Unusual peak-broadening effects are found, which cannot be explained using standard models. The modeling of the diffraction patterns with a statistic variation of the molecules reveal that a specific type of molecular disorder is responsible for the observed peak-broadening phenomena: the known head-to-head stacking within the crystalline phase is disturbed by the statistic integration of reversed (or flipped) molecules. It is found that 7-15% of the molecules are integrated in a reversed way, and these fractions are correlated with cooling rates during the sample preparation procedure. Temperature-dependent in situ experiments reveal that the defects can be healed by approaching the transition from the crystalline state to the smectic E state at a temperature of 145 °C. This work identifies and quantifies a specific crystalline defect type within thin films of an asymmetric rodlike conjugated molecule, which is caused by the crystallization kinetics.

Hofer, S., Unterkofler, J., Kaltenegger, M., Schweicher, G., Ruzie, C., Tamayo, A., et al. (2021). Molecular Disorder in Crystalline Thin Films of an Asymmetric BTBT Derivative. CHEMISTRY OF MATERIALS, 33(4), 1455-1461 [10.1021/acs.chemmater.0c04725].

Molecular Disorder in Crystalline Thin Films of an Asymmetric BTBT Derivative

Sanzone A.;Beverina L.;
2021

Abstract

The molecule 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) is an organic semiconductor with outstanding performance in thin-film transistors. The asymmetric shape of the molecule causes an unusual phase behavior, which is a result of a distinct difference in the molecular arrangement between the head-to-head stacking of the molecules versus head-to-tail stacking. Thin films are prepared at elevated temperatures by crystallization from melt under controlled cooling rates, thermal-gradient crystallization, and bar coating at elevated temperatures. The films are investigated using X-ray diffraction techniques. Unusual peak-broadening effects are found, which cannot be explained using standard models. The modeling of the diffraction patterns with a statistic variation of the molecules reveal that a specific type of molecular disorder is responsible for the observed peak-broadening phenomena: the known head-to-head stacking within the crystalline phase is disturbed by the statistic integration of reversed (or flipped) molecules. It is found that 7-15% of the molecules are integrated in a reversed way, and these fractions are correlated with cooling rates during the sample preparation procedure. Temperature-dependent in situ experiments reveal that the defects can be healed by approaching the transition from the crystalline state to the smectic E state at a temperature of 145 °C. This work identifies and quantifies a specific crystalline defect type within thin films of an asymmetric rodlike conjugated molecule, which is caused by the crystallization kinetics.
Articolo in rivista - Articolo scientifico
organic electronics
English
1455
1461
7
Hofer, S., Unterkofler, J., Kaltenegger, M., Schweicher, G., Ruzie, C., Tamayo, A., et al. (2021). Molecular Disorder in Crystalline Thin Films of an Asymmetric BTBT Derivative. CHEMISTRY OF MATERIALS, 33(4), 1455-1461 [10.1021/acs.chemmater.0c04725].
Hofer, S; Unterkofler, J; Kaltenegger, M; Schweicher, G; Ruzie, C; Tamayo, A; Salzillo, T; Mas-Torrent, M; Sanzone, A; Beverina, L; Geerts, Y; Resel, R
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/318798
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